§ 59.216c.  Pasteurizers employing regenerative heating.

 (a)  Milk-to-milk regenerative heating. Pasteurizers employing milk-to-milk regenerating heating with both sides closed to the atmosphere shall comply with the following or equally satisfactory specifications:

   (1)  Regenerators shall be constructed, installed, and operated so that pasteurized milk in the regenerator will automatically be under greater pressure than raw milk in the regenerator at all times.

   (2)  The pasteurized milk, between its outlet from the regenerator and the nearest point downstream open to the atmosphere, shall rise to a vertical elevation of 12 inches above the highest raw milk level downstream from the constant-level tank and shall be open to the atmosphere at this or a higher elevation. A vacuum breaker shall be considered open to the atmosphere.

   (3)  The overflow of the top rim of the constant-level raw milk tank shall always be lower than the lowest milk level in the regenerator.

   (4)  No pump or flow-promoting device which can affect the proper pressure relationships within the regenerator shall be located between the pasteurized milk outlet from the regenerator and the nearest downstream point open to the atmosphere.

   (5)  No pump shall be located between the raw milk inlet to the regenerator and the raw milk supply tank unless it is designed and installed to operate only when milk is flowing through the pasteurized milk side of the regenerator and when the pressure of the pasteurized milk is higher than the maximum pressure produced by the pump. This may be accomplished by wiring the booster pump so that it cannot operate unless:

     (i)   the metering pump is in operation;

     (ii)   the flow-diversion device is in forward-flow position; and

     (iii)   the pasteurized milk pressure exceeds by at least one psi the maximum pressure developed by the booster pump; pressure gauges shall be installed at the raw milk inlet to the regenerator and the pasteurized milk outlet of the regenerator or the outlet of the cooler. The accuracy of required pressure gauges will be checked by the Department.

   (6)  The motor, casing, and impeller of the booster pump shall be identified and such records thereof maintained as directed by the Department. All electric wiring interconnections should be in permanent conduit—except that rubber covered cable may be used for final connections—with no electrical connections to defeat the purpose of any provisions of this section, § §  59.216, 59.216a, 59.216b and 59.216d.

   (7)  All raw milk in the regenerator shall drain freely back into the constant-level raw milk tank when the raw milk pumps are shut down and the raw milk outlet from the regenerator is disconnected.

   (8)  When vacuum equipment is located downstream from the flow-diversion device, means shall be provided to prevent the lowering of the pasteurized milk level in the regenerator during periods of diverted flow or shut-down. An effective vacuum breaker, and an automatic means of preventing a negative pressure shall be installed in the line between the vacuum chamber and the pasteurized milk to the regenerator.

   (9)  In the case of HHST pasteurization systems utilizing the temperatures of 191°F (89°C) and above and holding times of one second or less, with the flow-diversion device located downstream from the regenerator and/or cooler section, the requirement that the pasteurized product from the outlet of the regenerator or cooler shall rise to vertical elevation of 12 inches above the highest raw product level downstream from the constant-level tank and shall be open to the atmosphere at this or a higher elevation may be eliminated; provided that a differential pressure controller is used to monitor the highest pressure in the raw product side of the regenerator and the lowest pressure in the pasteurized side of the regenerator; and provided that the controller is interlocked with the flow-diversion device and is set and sealed so that whenever improper pressures occur in the regenerator, forward flow of product is automatically prevented and will not start again until all product-contact surfaces between the holding tube and flow-diversion device have been held at or above the required pasteurization temperature continuously and simultaneously for at least the required pasteurization time.

   (10)  When culinary steam is introduced directly into milk or milk products as the means of terminal heating to achieve pasteurization temperature and vacuum equipment is located downstream from the holding tube, the requirement that a vacuum breaker be installed at the inlet to the pasteurized side of the regenerator may be eliminated; provided that the differential pressure controller is installed and wired to control the flow-diversion device as described in paragraph (9).

   (11)  When the differential pressure controller is installed and wired to control the flow-diversion device as described in paragraph (9), the raw product booster pump may be permitted to run at all times, provided the metering pump is in operation.

 (b)  Milk-to-water-to-milk regenerative heating. Milk-to-water-to-milk regenerators with both the milk and the heat-transfer water in the raw milk section closed to the atmosphere shall comply with the following or equally satisfactory specifications:

   (1)  Regenerators of this type shall be so designed, installed, and operated that the heat-transfer-medium side of the regenerator in the raw milk section will automatically be under greater pressure than the raw side at all times.

   (2)  The heat-transfer water shall be safe and the heat-transfer water shall be in a covered tank which is open to the atmosphere at an elevation higher, by at least 12 inches, than any raw milk level downstream from the constant-level tank. The heat-transfer water between its outlet from the regenerator and the nearest point downstream open to the atmosphere shall rise to a vertical elevation of at least 12 inches above any raw milk in the system and shall be open to the atmosphere at this or a higher elevation.

   (3)  The heat-transfer water circuit shall be full of water at the beginning of the run, and all loss of water from the circuit shall automatically and immediately replenish whenever raw milk is present in the regenerator.

   (4)  The overflow of the top rim of the constant level raw milk tank shall always be lower than the lowest milk level in the raw milk section of the regenerator. The regenerator shall be designed and installed so that all raw milk shall drain freely back to the upstream supply tank when the raw milk pumps are shut down and the raw milk line is disconnected from the regenerator outlet.

   (5)  No pump shall be located between the raw milk inlet to the regenerator and the raw milk supply tank unless it is designed and installed to operate only when water is flowing through the heat-transfer section of the regenerator and when the pressure of the heat-transfer water is higher than the pressure of the raw milk. This may be accomplished by wiring the booster pump so that it cannot operate unless:

     (i)   The heat-transfer water pump is in operation.

     (ii)   The heat-transfer water pressure exceeds, by at least one pound per square inch, the raw milk pressure in the regenerator; pressure gauges shall be installed at the raw milk inlet and the heat-transfer water outlet of the regenerator.